/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.commons.net.ftp.parser;

import java.text.ParseException;
import java.util.List;

import org.apache.commons.net.ftp.FTPClientConfig;
import org.apache.commons.net.ftp.FTPFile;

/**
 * Implementation of FTPFileEntryParser and FTPFileListParser for IBM zOS/MVS
 * Systems.
 * 
 * @author <a href="henrik.sorensen@balcab.ch">Henrik Sorensen</a>
 * @author <a href="jnadler@srcginc.com">Jeff Nadler</a>
 * @author <a href="wnoto@openfinance.com">William Noto</a>
 * 
 * @version $Id$
 * @see org.apache.commons.net.ftp.FTPFileEntryParser FTPFileEntryParser (for
 *      usage instructions)
 */
public class MVSFTPEntryParser extends ConfigurableFTPFileEntryParserImpl {

	static final int UNKNOWN_LIST_TYPE = -1;
	static final int FILE_LIST_TYPE = 0;
	static final int MEMBER_LIST_TYPE = 1;
	static final int UNIX_LIST_TYPE = 2;
	static final int JES_LEVEL_1_LIST_TYPE = 3;
	static final int JES_LEVEL_2_LIST_TYPE = 4;

	private int isType = UNKNOWN_LIST_TYPE;

	/**
	 * Fallback parser for Unix-style listings
	 */
	private UnixFTPEntryParser unixFTPEntryParser;

	/**
	 * Dates are ignored for file lists, but are used for member lists where
	 * possible
	 */
	static final String DEFAULT_DATE_FORMAT = "yyyy/MM/dd HH:mm"; // 2001/09/18
																	// 13:52

	/**
	 * Matches these entries: Volume Unit Referred Ext Used Recfm Lrecl BlkSz
	 * Dsorg Dsname B10142 3390 2006/03/20 2 31 F 80 80 PS MDI.OKL.WORK
	 * 
	 */
	static final String FILE_LIST_REGEX = "\\S+\\s+" + // volume
																// ignored
			"\\S+\\s+" + // unit - ignored
			"\\S+\\s+" + // access date - ignored
			"\\S+\\s+" + // extents -ignored
			"\\S+\\s+" + // used - ignored
			"[FV]\\S*\\s+" + // recfm - must start with F or V
			"\\S+\\s+" + // logical record length -ignored
			"\\S+\\s+" + // block size - ignored
			"(PS|PO|PO-E)\\s+" + // Dataset organisation. Many exist
			// but only support: PS, PO, PO-E
			"(\\S+)\\s*"; // Dataset Name (file name)

	/**
	 * Matches these entries: Name VV.MM Created Changed Size Init Mod Id
	 * TBSHELF 01.03 2002/09/12 2002/10/11 09:37 11 11 0 KIL001
	 */
	static final String MEMBER_LIST_REGEX = "(\\S+)\\s+" + // name
			"\\S+\\s+" + // version, modification (ignored)
			"\\S+\\s+" + // create date (ignored)
			"(\\S+)\\s+" + // modification date
			"(\\S+)\\s+" + // modification time
			"\\S+\\s+" + // size in lines (ignored)
			"\\S+\\s+" + // size in lines at creation(ignored)
			"\\S+\\s+" + // lines modified (ignored)
			"\\S+\\s*"; // id of user who modified (ignored)

	/**
	 * Matches these entries, note: no header: IBMUSER1 JOB01906 OUTPUT 3 Spool
	 * Files 012345678901234567890123456789012345678901234 1 2 3 4
	 */
	static final String JES_LEVEL_1_LIST_REGEX = "(\\S+)\\s+" + // job
																		// name
																		// ignored
			"(\\S+)\\s+" + // job number
			"(\\S+)\\s+" + // job status (OUTPUT,INPUT,ACTIVE)
			"(\\S+)\\s+" + // number of spool files
			"(\\S+)\\s+" + // Text "Spool" ignored
			"(\\S+)\\s*" // Text "Files" ignored
	;

	/**
	 * JES INTERFACE LEVEL 2 parser Matches these entries: JOBNAME JOBID OWNER
	 * STATUS CLASS IBMUSER1 JOB01906 IBMUSER OUTPUT A RC=0000 3 spool files
	 * IBMUSER TSU01830 IBMUSER OUTPUT TSU ABEND=522 3 spool files
	 * 012345678901234567890123456789012345678901234 1 2 3 4
	 * 012345678901234567890123456789012345678901234567890
	 */

	static final String JES_LEVEL_2_LIST_REGEX = "(\\S+)\\s+" + // job
																		// name
																		// ignored
			"(\\S+)\\s+" + // job number
			"(\\S+)\\s+" + // owner ignored
			"(\\S+)\\s+" + // job status (OUTPUT,INPUT,ACTIVE) ignored
			"(\\S+)\\s+" + // job class ignored
			"(\\S+).*" // rest ignored
	;

	/*
	 * ---------------------------------------------------------------------
	 * Very brief and incomplete description of the zOS/MVS-filesystem. (Note:
	 * "zOS" is the operating system on the mainframe, and is the new name for
	 * MVS)
	 * 
	 * The filesystem on the mainframe does not have hierarchal structure as for
	 * example the unix filesystem. For a more comprehensive description, please
	 * refer to the IBM manuals
	 * 
	 * @LINK:
	 * http://publibfp.boulder.ibm.com/cgi-bin/bookmgr/BOOKS/dgt2d440/CONTENTS
	 * 
	 * 
	 * Dataset names =============
	 * 
	 * A dataset name consist of a number of qualifiers separated by '.', each
	 * qualifier can be at most 8 characters, and the total length of a dataset
	 * can be max 44 characters including the dots.
	 * 
	 * 
	 * Dataset organisation ====================
	 * 
	 * A dataset represents a piece of storage allocated on one or more disks.
	 * The structure of the storage is described with the field dataset
	 * organinsation (DSORG). There are a number of dataset organisations, but
	 * only two are usable for FTP transfer.
	 * 
	 * DSORG: PS: sequential, or flat file PO: partitioned dataset PO-E:
	 * extended partitioned dataset
	 * 
	 * The PS file is just a flat file, as you would find it on the unix file
	 * system.
	 * 
	 * The PO and PO-E files, can be compared to a single level directory
	 * structure. A PO file consist of a number of dataset members, or files if
	 * you will. It is possible to CD into the file, and to retrieve the
	 * individual members.
	 * 
	 * 
	 * Dataset record format =====================
	 * 
	 * The physical layout of the dataset is described on the dataset itself.
	 * There are a number of record formats (RECFM), but just a few is relavant
	 * for the FTP transfer.
	 * 
	 * Any one beginning with either F or V can safely used by FTP transfer. All
	 * others should only be used with great care, so this version will just
	 * ignore the other record formats. F means a fixed number of records per
	 * allocated storage, and V means a variable number of records.
	 * 
	 * 
	 * Other notes ===========
	 * 
	 * The file system supports automatically backup and retrieval of datasets.
	 * If a file is backed up, the ftp LIST command will return: ARCIVE Not
	 * Direct Access Device KJ.IOP998.ERROR.PL.UNITTEST
	 * 
	 * 
	 * Implementation notes ====================
	 * 
	 * Only datasets that have dsorg PS, PO or PO-E and have recfm beginning
	 * with F or V, is fully parsed.
	 * 
	 * The following fields in FTPFile is used: FTPFile.Rawlisting: Always set.
	 * FTPFile.Type: DIRECTORY_TYPE or FILE_TYPE or UNKNOWN FTPFile.Name: name
	 * FTPFile.Timestamp: change time or null
	 * 
	 * 
	 * 
	 * Additional information ======================
	 * 
	 * The MVS ftp server supports a number of features via the FTP interface.
	 * The features are controlled with the FTP command quote site filetype=<SEQ|JES|DB2>
	 * SEQ is the default and used for normal file transfer JES is used to
	 * interact with the Job Entry Subsystem (JES) similar to a job scheduler
	 * DB2 is used to interact with a DB2 subsystem
	 * 
	 * This parser supports SEQ and JES.
	 * 
	 * 
	 * 
	 * 
	 * 
	 * 
	 */

	/**
	 * The sole constructor for a MVSFTPEntryParser object.
	 * 
	 */
	public MVSFTPEntryParser() {
		super(""); // note the regex is set in preParse.
		super.configure(null); // configure parser with default configurations
	}

	/**
	 * Parses a line of an z/OS - MVS FTP server file listing and converts it
	 * into a usable format in the form of an <code> FTPFile </code> instance.
	 * If the file listing line doesn't describe a file, then
	 * <code> null </code> is returned. Otherwise a <code> FTPFile </code>
	 * instance representing the file is returned.
	 * 
	 * @param entry
	 *            A line of text from the file listing
	 * @return An FTPFile instance corresponding to the supplied entry
	 */
	public FTPFile parseFTPEntry(String entry) {
		boolean isParsed = false;
		FTPFile f = new FTPFile();

		if (isType == FILE_LIST_TYPE)
			isParsed = parseFileList(f, entry);
		else if (isType == MEMBER_LIST_TYPE) {
			isParsed = parseMemberList(f, entry);
			if (!isParsed)
				isParsed = parseSimpleEntry(f, entry);
		} else if (isType == UNIX_LIST_TYPE) {
			isParsed = parseUnixList(f, entry);
		} else if (isType == JES_LEVEL_1_LIST_TYPE) {
			isParsed = parseJeslevel1List(f, entry);
		} else if (isType == JES_LEVEL_2_LIST_TYPE) {
			isParsed = parseJeslevel2List(f, entry);
		}

		if (!isParsed)
			f = null;
		
		return f;
	}

	/**
	 * Parse entries representing a dataset list. Only datasets with DSORG PS or
	 * PO or PO-E and with RECFM F* or V* will be parsed.
	 * 
	 * Format of ZOS/MVS file list: 1 2 3 4 5 6 7 8 9 10 Volume Unit Referred
	 * Ext Used Recfm Lrecl BlkSz Dsorg Dsname B10142 3390 2006/03/20 2 31 F 80
	 * 80 PS MDI.OKL.WORK ARCIVE Not Direct Access Device
	 * KJ.IOP998.ERROR.PL.UNITTEST B1N231 3390 2006/03/20 1 15 VB 256 27998 PO
	 * PLU B1N231 3390 2006/03/20 1 15 VB 256 27998 PO-E PLB
	 * 
	 * ----------------------------------- Group within Regex [1] Volume [2]
	 * Unit [3] Referred [4] Ext: number of extents [5] Used [6] Recfm: Record
	 * format [7] Lrecl: Logical record length [8] BlkSz: Block size [9] Dsorg:
	 * Dataset organisation. Many exists but only support: PS, PO, PO-E [10]
	 * Dsname: Dataset name
	 * 
	 * Note: When volume is ARCIVE, it means the dataset is stored somewhere in
	 * a tape archive. These entries is currently not supported by this parser.
	 * A null value is returned.
	 * 
	 * @param f:
	 *            will be updated with Name, Type, Timestamp if parsed.
	 * @param zosDirectoryEntry
	 * @return true: entry was parsed, false: entry was not parsed.
	 */
	private boolean parseFileList(FTPFile file, String entry) {
		if (matches(entry)) {
			file.setRawListing(entry);
			String name = group(2);
			String dsorg = group(1);
			file.setName(name);

			// DSORG
			if ("PS".equals(dsorg)) {
				file.setType(FTPFile.FILE_TYPE);
			} 
			else if ("PO".equals(dsorg) || "PO-E".equals(dsorg)) {
				// regex already ruled out anything other than PO or PO-E
				file.setType(FTPFile.DIRECTORY_TYPE);
			} 
			else {
				return false;
			}
			
			return true;
		}
		
		return false;
	}

	/**
	 * Parse entries within a partitioned dataset.
	 * 
	 * Format of a memberlist within a PDS: 1 2 3 4 5 6 7 8 9 Name VV.MM Created
	 * Changed Size Init Mod Id TBSHELF 01.03 2002/09/12 2002/10/11 09:37 11 11
	 * 0 KIL001 TBTOOL 01.12 2002/09/12 2004/11/26 19:54 51 28 0 KIL001
	 * 
	 * ------------------------------------------- [1] Name [2] VV.MM: Version .
	 * modification [3] Created: yyyy / MM / dd [4,5] Changed: yyyy / MM / dd
	 * HH:mm [6] Size: number of lines [7] Init: number of lines when first
	 * created [8] Mod: number of modified lines a last save [9] Id: User id for
	 * last update
	 * 
	 * 
	 * @param f:
	 *            will be updated with Name, Type and Timestamp if parsed.
	 * @param zosDirectoryEntry
	 * @return true: entry was parsed, false: entry was not parsed.
	 */
	private boolean parseMemberList(FTPFile file, String entry) {
		if (matches(entry)) {
			file.setRawListing(entry);
			String name = group(1);
			String datestr = group(2) + " " + group(3);
			file.setName(name);
			file.setType(FTPFile.FILE_TYPE);
			try {
				file.setTimestamp(super.parseTimestamp(datestr));
			} catch (ParseException e) {
				e.printStackTrace();
				// just ignore parsing errors.
				// TODO check this is ok
				return false; // this is a parsing failure too.
			}
			return true;
		}

		return false;
	}

	/**
	 * Assigns the name to the first word of the entry. Only to be used from a
	 * safe context, for example from a memberlist, where the regex for some
	 * reason fails. Then just assign the name field of FTPFile.
	 * 
	 * @param file
	 * @param entry
	 * @return
	 */
	private boolean parseSimpleEntry(FTPFile file, String entry) {
		if (entry != null && entry.length() > 0) {
			file.setRawListing(entry);
			String name = entry.split(" ")[0];
			file.setName(name);
			file.setType(FTPFile.FILE_TYPE);
			return true;
		}
		return false;
	}

	/**
	 * Parse the entry as a standard unix file. Using the UnixFTPEntryParser.
	 * 
	 * @param file
	 * @param entry
	 * @return true: entry is parsed, false: entry could not be parsed.
	 */
	private boolean parseUnixList(FTPFile file, String entry) {
		file = unixFTPEntryParser.parseFTPEntry(entry);
		if (file == null)
			return false;
		return true;
	}

	/**
	 * Matches these entries, note: no header: [1] [2] [3] [4] [5] IBMUSER1
	 * JOB01906 OUTPUT 3 Spool Files
	 * 012345678901234567890123456789012345678901234 1 2 3 4
	 * ------------------------------------------- Group in regex [1] Job name
	 * [2] Job number [3] Job status (INPUT,ACTIVE,OUTPUT) [4] Number of sysout
	 * files [5] The string "Spool Files"
	 * 
	 * 
	 * @param f:
	 *            will be updated with Name, Type and Timestamp if parsed.
	 * @param zosDirectoryEntry
	 * @return true: entry was parsed, false: entry was not parsed.
	 */
	private boolean parseJeslevel1List(FTPFile file, String entry) {
		if (matches(entry)) {
			if (group(3).equalsIgnoreCase("OUTPUT")) {
				file.setRawListing(entry);
				String name = group(2); /* Job Number, used by GET */
				file.setName(name);
				file.setType(FTPFile.FILE_TYPE);
				return true;
			}
		}

		return false;
	}

	/**
	 * Matches these entries, note: no header: [1] [2] [3] [4] [5] JOBNAME JOBID
	 * OWNER STATUS CLASS IBMUSER1 JOB01906 IBMUSER OUTPUT A RC=0000 3 spool
	 * files IBMUSER TSU01830 IBMUSER OUTPUT TSU ABEND=522 3 spool files
	 * 012345678901234567890123456789012345678901234 1 2 3 4
	 * ------------------------------------------- Group in regex [1] Job name
	 * [2] Job number [3] Owner [4] Job status (INPUT,ACTIVE,OUTPUT) [5] Job
	 * Class [6] The rest
	 * 
	 * 
	 * @param f:
	 *            will be updated with Name, Type and Timestamp if parsed.
	 * @param zosDirectoryEntry
	 * @return true: entry was parsed, false: entry was not parsed.
	 */
	private boolean parseJeslevel2List(FTPFile file, String entry) {
		if (matches(entry)) {
			if (group(4).equalsIgnoreCase("OUTPUT")) {
				file.setRawListing(entry);
				String name = group(2); /* Job Number, used by GET */
				file.setName(name);
				file.setType(FTPFile.FILE_TYPE);
				return true;
			}
		}

		return false;
	}

	/**
	 * preParse is called as part of the interface. Per definition is is called
	 * before the parsing takes place. Three kind of lists is recognize:
	 * z/OS-MVS File lists z/OS-MVS Member lists unix file lists
	 */
	public List preParse(List orig) {
		// simply remove the header line. Composite logic will take care of the
		// two different types of
		// list in short order.
		if (orig != null && orig.size() > 0) {
			String header = (String) orig.get(0);
			if (header.indexOf("Volume") >= 0 && header.indexOf("Dsname") >= 0) {
				setType(FILE_LIST_TYPE);
				super.setRegex(FILE_LIST_REGEX);
			} else if (header.indexOf("Name") >= 0 && header.indexOf("Id") >= 0) {
				setType(MEMBER_LIST_TYPE);
				super.setRegex(MEMBER_LIST_REGEX);
			} else if (header.indexOf("total") == 0) {
				setType(UNIX_LIST_TYPE);
				unixFTPEntryParser = new UnixFTPEntryParser();
			} else if (header.indexOf("Spool Files") >= 30) {
				setType(JES_LEVEL_1_LIST_TYPE);
				super.setRegex(JES_LEVEL_1_LIST_REGEX);
			} else if (header.indexOf("JOBNAME") == 0
					&& header.indexOf("JOBID") > 8) {// header contains JOBNAME JOBID OWNER									// STATUS CLASS
				setType(JES_LEVEL_2_LIST_TYPE);
				super.setRegex(JES_LEVEL_2_LIST_REGEX);
			} else {
				setType(UNKNOWN_LIST_TYPE);
			}
			
			if (isType != JES_LEVEL_1_LIST_TYPE) { // remove header is necessary
				orig.remove(0);
			}
		}
		
		return orig;
	}
	
	/**
	 * Explicitly set the type of listing being processed.
	 * @param type The listing type.
	 */
	void setType(int type) {
		isType = type;
	}

	/* 
	 * @return
	 */
	protected FTPClientConfig getDefaultConfiguration() {
		return new FTPClientConfig(FTPClientConfig.SYST_MVS,
				DEFAULT_DATE_FORMAT, null, null, null, null);
	}

}
